galaxy5: cleanup

* Update cm.dependencies
* Remove all unnecessary config & code that belongs in shared config
* Revert to kernel 2.6 & ar6000 driver
* Remove custom init.gt-i5500board.rc (shared init now compatible)
* Move custom hciattach & g5sensord services to init.parts.rc
* Update dalvik heap sizes (heapsize=32m, heapgrowlimit=24m,
  heaptargetutilization=0.25)
* Remove ro.vold.umsdirtyratio=20 (drastically slows UMS speed)
* Remove ALL LDPI overlay; anything that needs to be restored
  belongs in ldpi-common
* Use minimal font footprint (saves ~2MB)
* Build userspace libs/daemons using kernel source's headers
* Enable TARRGET_ARCH_LOWMEM to free memory resources
* Update dynamic lowmemorykiller values to Samsung Froyo defaults

Change-Id: I092f8f0beda0f1b715ef1b1f7ee898e9e6f16f8f