Amend description of SimpleCommand class
Fix spacing in file header comments

In some source files there was only one space before "*/" at the end of
the header comment while there were two in the other files. For
consistency, there should always be two spaces.

Note that we have (exceptionally) two spaces between each sentence in
header comments, while we have only one in normal comments.
Add checkheaderinclude.sh test script
Fix include guard macro name in SourceBuffer.hh

Include guard macro names should match the pathname.
Add buildconfig.h header file
Define CATCH_CONFIG_SFINAE macro

The CATCH_CONFIG_SFINAE macro allows Catch to select appropriate
template overloads to print compared values correctly.
Undefine __STRICT_ANSI__ for Cygwin
Merge pull request #14 from magicant/refactor/commonheader

Add buildconfig.h header file
Merge pull request #15 from magicant/fix/misc

Miscellaneous fixes