Add local .gitignore file
Improve .gitignore file

This commit cleans up the .gitignore file. It now only ignores generated
files that are always created in the source tree.
Merge remote-tracking branch 'upstream/develop' into develop
Random typo corrections
Merge remote-tracking branch 'upstream/develop' into develop

Conflicts:
	src/p8est_mesh.h
Move .gitignore file to .git/info/exclude
Merge remote-tracking branch 'ethan/develop'
Fix comment typos