Added intel & foss toolchains
Merge pull request #940 from hpcugent/develop

release EasyBuild v1.13.0
bump version to 1.13.1dev
don't tweak easyconfigs if they were generated
make ModulesTool a singleton, use 'module use/unuse' rather than fiddling with $MODULEPATH, use $LMOD_QUIET rather than $LMOD_EXPERT
fix deprecation message in systemtools.py
fix unit tests now that ModulesTool is a singleton and use/unuse should be used
purge out any loaded modules before each test

Conflicts:
	test/framework/modules.py
clean up purging on modified $MODULEPATH in modulestool.py unit test module

Conflicts:
	test/framework/modulestool.py
purge *after* setting $MODULEPATH
also enable $LMOD_EXPERT, still requires with Lmod version prior to 5.6
add commandline override for optarch toolchain setting
added unit test.
fix unit test.
override optarch after arch check
coding by trial and error.
made unittest uglier, but works now. 100%. every time. on my machine.
don't run 'module update', there's no need to
added set_alias function
added modextraalias var to easyconfig/default.py