removed undo/redo code snippet
removed microseconds from output
removed code snippets for set_cache_size
more prose than lists. explained the benefits and less the underlying code.
Merge branch 'master' of github.com:sunpy/sunpy-0.4-paper into database

Conflicts:
	3-5-Database.tex
Merge pull request #26 from derdon/database

database, 2nd draft