build: build Exchange

This will allow exchange to build for real :-)

Change-Id: I281b3c2b4617c8a3a800f205898f91270fa43acc
Fix perm for boot_flash_from_image

Change-Id: I656018bd9dfa79646233a8a5b72164f7fd93d880
Signed-off-by: Josue Rivera <prbassplayer@gmail.com>
envsetup: add slimremote and cmremote commands in the same vane as aospremote and cafremote

Change-Id: Iedc1ed7c83691ca53a4ed3b2ac3e1120f844e822