-Large speed up of package search: (5x-7x faster in various benchmarks)
--Improved text searching by being more cache and garbage collector friendly
--Removed repeated format conversion of generic icons
--Review images next to each package are now created completely in memory instead being written to a temporary file
--Sorting of package list is done on results instead of complete list

-Number of initial search results can be limited but will automatically load more packages when user scrolls to the bottom (up to 260x faster to start showing results for searches like 'a', 122356.112ms -> 463.111ms)
--This load is based on the existing automatic load when viewing a whole category

-Clean up of some unnecessary code duplication
Merge branch 'master' of https://github.com/LukePH/mintinstall into LukePH-master

Conflicts:
	usr/lib/linuxmint/mintInstall/mintinstall.py