PERF: update asv.conf.json to work with both conda and virtualenv

Add requirements rules for conda and virtualenv (requires asv git
version). Enable asv wheel cache.

Author: pv

asv_bench/asv.conf.json

@@ -30,24 +30,62 @@
 
     // The matrix of dependencies to test.  Each key is the name of a
     // package (in PyPI) and the values are version numbers.  An empty
-    // list indicates to just test against the default (latest)
-    // version.
+    // list or empty string indicates to just test against the default
+    // (latest) version. null indicates that the package is to not be
+    // installed. If the package to be tested is only available from
+    // PyPi, and the 'environment_type' is conda, then you can preface
+    // the package name by 'pip+', and the package will be installed via
+    // pip (with all the conda available packages installed first,
+    // followed by the pip installed packages).
     "matrix": {
-        // To run against multiple versions, replace with
-        // "numpy": ["1.7", "1.9"],
         "numpy": [],
         "Cython": [],
         "matplotlib": [],
         "sqlalchemy": [],
         "scipy": [],
         "numexpr": [],
-        "pytables": [],
+        "pytables": [null, ""],  // platform dependent, see excludes below
+        "tables": [null, ""],
+        "libpython": [null, ""],
         "openpyxl": [],
         "xlsxwriter": [],
         "xlrd": [],
         "xlwt": []
     },
 
+    // Combinations of libraries/python versions can be excluded/included
+    // from the set to test. Each entry is a dictionary containing additional
+    // key-value pairs to include/exclude.
+    //
+    // An exclude entry excludes entries where all values match. The
+    // values are regexps that should match the whole string.
+    //
+    // An include entry adds an environment. Only the packages listed
+    // are installed. The 'python' key is required. The exclude rules
+    // do not apply to includes.
+    //
+    // In addition to package names, the following keys are available:
+    //
+    // - python
+    //     Python version, as in the *pythons* variable above.
+    // - environment_type
+    //     Environment type, as above.
+    // - sys_platform
+    //     Platform, as in sys.platform. Possible values for the common
+    //     cases: 'linux2', 'win32', 'cygwin', 'darwin'.
+    "exclude": [
+        // On conda install pytables, otherwise tables
+        {"environment_type": "conda", "tables": ""},
+        {"environment_type": "conda", "pytables": null},
+        {"environment_type": "virtualenv", "tables": null},
+        {"environment_type": "virtualenv", "pytables": ""},
+        // On conda&win32, install libpython
+        {"sys_platform": "(?!win32).*", "libpython": ""},
+        {"sys_platform": "win32", "libpython": null},
+        {"environment_type": "(?!conda).*", "libpython": ""}
+    ],
+    "include": [],
+
     // The directory (relative to the current directory) that benchmarks are
     // stored in.  If not provided, defaults to "benchmarks"
     // "benchmark_dir": "benchmarks",
@@ -56,7 +94,6 @@
     // environments in.  If not provided, defaults to "env"
     // "env_dir": "env",
 
-
     // The directory (relative to the current directory) that raw benchmark
     // results are stored in.  If not provided, defaults to "results".
     // "results_dir": "results",
@@ -66,5 +103,23 @@
     // "html_dir": "html",
 
     // The number of characters to retain in the commit hashes.
-    // "hash_length": 8
+    // "hash_length": 8,
+
+    // `asv` will cache wheels of the recent builds in each
+    // environment, making them faster to install next time.  This is
+    // number of builds to keep, per environment.
+    "wheel_cache_size": 8,
+
+    // The commits after which the regression search in `asv publish`
+    // should start looking for regressions. Dictionary whose keys are
+    // regexps matching to benchmark names, and values corresponding to
+    // the commit (exclusive) after which to start looking for
+    // regressions.  The default is to start from the first commit
+    // with results. If the commit is `null`, regression detection is
+    // skipped for the matching benchmark.
+    //
+    // "regressions_first_commits": {
+    //    "some_benchmark": "352cdf",  // Consider regressions only after this commit
+    //    "another_benchmark": null,   // Skip regression detection altogether
+    // }
 }