A few more Java7 related clean ups.

- Separate SDK checking from version checking and
  make messages clearer.
- Add explicit source & target versions for javac to
  make things clearer.
- Rename flag from EXPERIMENTAL_USE_JAVA7_OPENJDK to
  EXPERIMENTAL_USE_JAVA7.
- Allow Oracle JDK 1.7 to be used on Mac OS, since there's
  no official OpenJDK support for that platform.

Change-Id: I454d2c917ed78f03ec7559a99659fefe7e7d50f3
Fix tools path on Mac OS for java 7.

Change-Id: Ieb72b9e10771ee372bacf20258242cb006c29fef
Explictly set WPA_SUPPLICANT_VERSION := VER_0_8_X for the generic devices

Since 558477c0b2a5a7db679c1ad7551d43e6364d1df2 in
external/wpa_supplicant_8 we don't have WPA_SUPPLICANT_VERSION default
to VER_0_8_X.
This fixes the SDK build.

Change-Id: Ib7a8e10705dc6b987b60b1308405e89eaa2a47c9
Delete board config for the unused "emulator" device.

Change-Id: I1e1d47fece4113be9f31f04775c5b310d28017e3
Push wpa_supplicant modules down to the leaf product config.

Since 558477c0b2a5a7db679c1ad7551d43e6364d1df2 in
external/wpa_supplicant_8 we don't need those modules if
WPA_SUPPLICANT_VERSION is not set by the BoardConfig.mk.

Actually the generic devices don't need them.

Change-Id: Iff7c1fbf483bd16d5f898836c4e7401d56def80f

Conflicts:
	target/product/core_tiny.mk
Merge "Explictly set WPA_SUPPLICANT_VERSION := VER_0_8_X for the generic devices"
Merge "Delete board config for the unused "emulator" device."
Merge "Push wpa_supplicant modules down to the leaf product config."
Merge "A few more Java7 related clean ups."
Merge "Fix tools path on Mac OS for java 7."
Merge Android Master.