cmakemake: don't use 'None' as CC or CXX if these environment variables are not
set.
Add Clang/3.2 easyblock
Fix copyright line
Removed unused imports, added docstring
Release the work under non-copyleft licenses
Clarify that tests were run before the test step
Refactor extract_step as suggested by Kenneth Hoste
Added docstring for configure_step
This statement fits into 120 columns, no need to split it
Fixup for CMakeMake API change.

CMakeMake.configure_step() parameter 'builddir' was renamed to 'srcdir',
because the name 'builddir' is incorrect.  This parameter specifies the path to
the directory containing source files.
Document API change in release notes
Move assertions under extra_options, so that easyconfig can control this
setting
Build all backends by default
Drop simple=False argument from run_cmd(), we are not using the output anyway
Add docstrings
Refactor handling '-j X' make option
Actually run tests for stage 3 in test_step instead of running them in
build_step
Merge branch 'clang' of github.com:gribozavr/easybuild-easyblocks into clang
keep backward compatibility w.r.t. builddir vs srcdir named argument
Refactor the code that translates environment variables to CMake command line
options to be table-driven, as suggested by Stijn De Weirdt.