recovery: Add support for performance control

 * Recovery will now set "recovery.perf.mode" to 1 before a
   backup/restore operation begins, and will set it back to 0
   when the operation is complete. It will also do this during
   package installations.
 * This allows devices to boot into recovery in a low-power mode,
   and bring up more cores and adjust other settings. Pigz is
   multithreaded, and enabling all cores vastly improves performance of
   compressed backups.
 * Device maintainers who wish to use this should configure their
   init.recovery script to trigger off of this property.

Change-Id: I174e45215ad1cd34a34b1af4486a64fb6e54134b
Hide install icon after success as it is done for regular zip installs

Change-Id: I932a6ecff0fb64913842c1ea4624021b476f7d46
Remove "Go Back" option from verify root and recovery options

These options only show when you are exiting recovery and there
is no where to "go back" to.

Patchset 1) initial
Patchset 2) change to ui_set_showing_back_button()
Patchset 3) revert settings before returning

Change-Id: I0aee8d0fbce9a5ff415b74b4a16e0d416042e307
do not error on missing sd-ext when wiping dalvik cache

Change-Id: I4cf817f05bd708fe2b7d6a5f20aab6ef2413d117
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: I39f7ae435a8ce3bad691e4b7c307db0bd8de1302
Enable perf mode only in tar(.gz) compress/extract wrappers

Performance mode is still enabled during install of update packages

Change-Id: I3256b9c93050f5240aa9b7c70211da7dcb53fb3a
Do not use performance mode during package install

this was causing a busy /system when usb cable is plugged in during install on some devices

Change-Id: Ief440ba3a32e9955a1244a9a93a5ac844176d13d