Avoid memory leaks when handling metadata strings

Don't duplicate strings when retrieveing metadata from media
files. As any requests for metadata strings would pass through
the binder, this would cause the reference to the duplicate string
to be lost, causing a memory leak as the duplicate would not be
freed.

Change-Id: I2593733472b1bb589bc502b2c11080f581015bb5
camera: add ISO3200 and ISO6400

This change adds camera ISO 3200 and 6400, needed by some camera hal.

Change-Id: I65172a7de6554c3c288f0a4153d3fcb432b70db8
camera: improve power mode support

This change improves the power mode support introduced in commit
eb01ea6cef737964a31ccad2506ae64c877e6223.

The power mode it's not exclusive of Sony phones.

Based on commit 7036d66bec7697160ba1b2e255f1e7fae0c8c435 from CAF,
branch ics_chocolate.

Change-Id: Ic71b780ef05bd833c0d44cf40afc5b82efd11697