Improve backup & wipe exclusion handling

Rename twrpDU.* to exclude.*
Remove global variable for du and replace with partition specific
variables.
Use separate exclusion lists for backups and wiping.
Clean up some includes
Fix some parenthesis in twrp.cpp that I messed up.

Note: twrpTarMain command line utility compiles but probably does
not work correctly yet due to not properly setting part_settings

Change-Id: Idec9c3e6a8782ba53f3420fa79ba33394f4f85fb