[MC] Add MagicCode support.

Change-Id: I3d4b4b1d2da8a286cfdfbe85feeda97e3d092feb
[MC] Restore timestamp check. Restore crc code but leave disabled.

Minimize textual diffs with non-MC Android.
The reason why Ingenic disabled the timestamp and crc checks is unclear.
MC does not make hidden changes to read-only codefiles, so both
the timestamp and crc checks should work okay with MC.
Possibly, Ingenic simply did not like spending additional boot time
on an functionally unnecessary crc check.  (The crc check was added
in a recent Android release.)

Change-Id: Ie2a3e55d1517b59ed2012c03ce4c1ab56dd25d98
[MC] Hide new fields of Build class from SDK users.

Android build scripts now restrict unapproved API extensions
beyond what Google formally exports to SDK users.

Change-Id: I01ff1eb8703b1c0a48873e837433417cf068fc54
Merge "[MC] Restore timestamp check. Restore crc code but leave disabled." into dev-mips-jb-mr1
[MC] Simplify & reduce bugs in Magiccode framework

Change default /proc/cpuinfo from Neon off, to Neon on.
Always give mips abi priority over arm abis.
Eliminate relative-codesize heuristics.
Eventually: armv7 should have priority over armv5 for most apps.
Temporarily: armv5 has priority over armv7 for most apps.
This can be forced back to armv7 for all apps, via magiccode_prefs.xml .
Rename /vendor/lib/ForceInstallArm.xml as /data/system/magiccode_prefs.xml .
Avoid dependence on alpha sorting of abi names in zip file.
Ignore app version string in searches of magiccode_prefs.
Eliminate most static vars.
Improve names.
Move vars from read-only Build class to NativeLibraryHelper class.
Move magiccode_prefs reader from (too-late point in) PackageManager
  to NativeLibraryHelper.  Add customizeAbiByAppname calls in
  all paths with known package names.  Fix boot-time bugs.
Replace INSTALL_FAILED_MIS_ABI by existing, diagnosed
   INSTALL_FAILED_CPU_ABI_INCOMPATIBLE.
Diagnose apks with x86 native code but not mips or selected arm.
Use max upper bound for possible native lib sizes rather than
   relying on unknown packageNames, or reporting sums over all abis.
Restore CRC calc on comparing previously-installed files.

Change-Id: I638d99d4ce99ee868df4b1659017489d1169c0ee
[MC] Selectively prefer Arm abi over Mips abi for some apks.

This feature of magiccode_prefs.xml was present in the original
Ingenic patches but lost in recent changes.  The xml file must again
list all possible abis for an apk in preference order, including mips.

Change-Id: I7614477d3c02d82fa4829ccff0d7b1f6b2218ba0