Add basic error checking to legacy property init

Let init and rename funcitons return success or failure values.

Change-Id: Ieed86cac8a0dcfd770a89dacc57fd306e7a6ad8d
Allow disabling legacy properties

Introduce TW_NO_LEGACY_PROPS flag for users that build TWRP in
non-kitkat trees and don't need the legacy prop environment.

Change-Id: Iacb2d9af7d7069acb3d0a96bb34f32ded6317a20
Cleanup DU Get_Folder_Size function

Change-Id: I3c686c7c3a171f130d299fae586dc811cad0d3a9
correctly mount tmpfs as /tmp in recovery

The syntax of init's mount command changed in April 2008 but
recovery's init.rc was never updated, so recovery's /tmp has been on
the root fs all this time.  Fix.

Also add /system/bin to the PATH in recovery, which is handy for
debugging.

Change-Id: I9e60d18803906bc75c263f12c8863cfd6a14147b
Fix /data backup size if contains media subdirs

/data/*/media directories are mistakenly being excluded from the size
calculation. Change to absolute dir exclude so that only /data/media is
excluded.

Change-Id: I6e97604d44e6ea2bdf7dfd8c68a2f90ba6d44415
if md5 check is not selected for subpartitions, don't check it.

Change-Id: I7248c75f17c6f82e098831c297c0662ef6ea289f
Merge "Add basic error checking to legacy property init" into android-4.4
Merge "correctly mount tmpfs as /tmp in recovery" into android-4.4
Merge "Cleanup DU Get_Folder_Size function" into android-4.4
Merge "Allow disabling legacy properties" into android-4.4
Merge "Fix /data backup size if contains media subdirs" into android-4.4
Merge "if md5 check is not selected for subpartitions, don't check it." into android-4.4
Merge remote-tracking branch 'omni/android-4.4' into android-4.4