glewinfo output is a .txt file

Fix perl @INC for scripts which include make.pl

In perl 5.26, and some earlier perls that have been proactively
patched (Debian's perl 5.24, for example), '.' was removed from @INC
for security reasons.  For details, see:
  http://blogs.perl.org/users/todd_rinaldo/2016/11/how-removing-from-inc-is-about-to-break-cpan.html
  https://www.masteringperl.org/2017/01/perl-v5-26-removes-from-inc-but-dont-think-youre-safe/
et cetera.

This breaks the generation scripts which source make.pl with
  do 'bin/make.pl'

Although this might be indicative that it's time to refactor these
scripts, I opted for the simplest possible fix for now: restoring '.'
to @INC in each script that depends on make.pl.

cmake: only install PDB files with msvc

Otherwise cmake windows builds with the mingw compiler are broken.

Added build note on README

Resolve issue #99: Removed /RTC1 flag in glew…

CMake: call find_package only if build_utils is enabled

Corrected spelling of needed in README.md.

"neded" -> "needed".

 - Used cmake regex to strip out the /RTC1 flag used by MSVC debug builds, which conflicts with the -nodefaultlib and -noentry flags.

Allows building both, shared-only or static-only.

Updated to reflect the concerns on issue #13

Fix wglGetProcAddress-related crash on 64-bit Windows with NOGDI defined

Fixed an issue on macs

- Fixed an issue that made compiling glew hang on macs
- Currently using Apple LLVM version 7.0.2 (clang-700.1.81)
- Added .DS_Store files to gitignore