gitignore: Create .gitignore file
gitignore: Create .gitignore file

This commit adds a new top-level .gitignore file and adds
ignores for the usual stuff:
  - Temporary/save files
  - Compiled object files
  - Other stuff created by the configure/build process

This will make 'git status' give much more relevant output.

project-zerus/cppunit,ryancalhoun/cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit,LesleyLai/cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit,project-zerus/cppunit,project-zerus/cppunit,LesleyLai/cppunit,ryancalhoun/cppunit,LesleyLai/cppunit,LesleyLai/cppunit,ryancalhoun/cppunit,ryancalhoun/cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit