modify build.gradle for Android-L.  Add BeaconTransmitter class
start adding android l scanning apis
Merge branch 'master' into android-l-apis

Conflicts:
	build.gradle
refactor scanning code to a new class so we can more easily implement Android L apis
add flag to conditionally use android l scanning apis
don't stop scanning on Android L if between scan cycle is zero
change naming convention for scan cycles
Merge branch 'master' into android-l-apis
Merge branch 'master' into android-l-apis
rework BeaconTransmitter to clean up interface and to be based on byte sequence generation from the BeaconParser
correct : to be = in example expression
harden beacon parser, transmitter and identifier classes to make arbitrary transmission settings more robust
Merge branch 'master' into android-l-apis

Conflicts:
	src/main/java/org/altbeacon/beacon/service/BeaconService.java
got compiling with SDK 21
switch target SDKS for methods requireing 5.0 and make scanning low latency
add ability to set background mode in service
fix stackoverflow exception per #51
Fix transmitter after successfully testing with Android 5 on Nexus 9
update comments for transmit frequency behavior

tested on a nexus 9
Merge branch 'master' into android-l-apis