Drop support for Python 3.3

There's a pending patch for clcache which improves behaviour when
clcache is run concurrently; however, this currently often (!) breaks
the CI tests with Python 3.3 due to a known bug in how the Python
subprocess module handles reading stdout/stderr. The Python bug report

  https://bugs.python.org/issue19575

has more on this topic. Alas, an inital workaround as posted on

  #294 (comment)

didn't help.

Since we already support Python 3.6 (i.e. we support the three most
recent minor versions), let's just drop Python 3.3 support.

Author: Frerich Raabe

CHANGELOG.md

@@ -7,6 +7,7 @@ clcache changelog
  * Bugfix: Fixed potential corruption of cache in case clcache is terminated
    while writing a cache entry or updating the cache statistics.
  * Internal: The automatic clcache tests are now executed with Python 3.6, too.
+ * Internal: Support for Python 3.3 has been dropped.
  * Bugfix: Fixed invoking the real compiler when using the `/Tc` or `/Tp`
    switches (GH #289)
 

appveyor.yml

@@ -8,7 +8,6 @@ environment:
     # AppVeyor installed Python versions
     # http://www.appveyor.com/docs/installed-software#python
 
-    - PYTHON_INSTALL: "C:\\Python33"
     - PYTHON_INSTALL: "C:\\Python34"
     - PYTHON_INSTALL: "C:\\Python35"
     - PYTHON_INSTALL: "C:\\Python36"

clcache.nuspec

@@ -11,7 +11,7 @@
     <description>
 A little Python script which attempts to avoid unnecessary recompilation by reusing previously cached object files if possible. It is meant to be called instead of the original 'cl.exe' executable. The script analyses the command line to decide whether source code is to be compiled. If so, a cache will be queried for a previously stored object file.
 
-This package contains an executable generated by `pyinstaller`, and is meant to facilitate the usage of `clcache.py` in a portable way. It is specially useful when needing to use `clcache.py` in environments with Python 2, since newer versions of `clcache.py` supports only Python 3.3+.
+This package contains an executable generated by `pyinstaller`, and is meant to facilitate the usage of `clcache.py` in a portable way. It is specially useful when needing to use `clcache.py` in environments with Python 2, since newer versions of `clcache.py` supports only Python 3.4+.
     </description>
     <projectUrl>https://github.com/frerich/clcache</projectUrl>
     <packageSourceUrl>https://github.com/frerich/clcache</packageSourceUrl>
@@ -29,4 +29,4 @@ Copyright (c)
   <files>
     <file src="clcache-{VERSION}\**" target="clcache-{VERSION}" />
   </files>  
-</package>
+</package>