getCurrentTime - interface function returns current playback time for specified recording
getCurrentTime - added to javascirpt interface
Fixed function which returning sample position index for given time in recording
Improved precision of 'getCurrentTime' function - removed latency from returning value [Bugfix]
Removed duplication. Added 'getTimestamp' for obtaining time as number
'getNowAsNumber' instead of 'getTimestamp' to clarify
Merge branch 'feature/playback-progress'

Conflicts:
	html/recorder.swf
MicrophoneLevel: added class dispatching level events
MicrophoneLevel: external interface for starting and stopping observation of level and dispatching external event
Minimal lifting of demo
MicrophoneLevel: Level bar added to demo
MicrophoneLevel: Updated README
MicrophoneLevel: checking microphone availability [Bugfix]
recorder.js: removed call of global variable in asynchronous callback. Compiled swf.
MicrophoneLevel: Custom Event class for microphone level
MicrophoneLevel: renamed flag 'isObserving' and added 'isObserving' getter
MicrophoneLevel: minor improvements: removed useless 'this' and renamed 'mic' variable
MicrophoneLevel: minor improvements: renamed const containing event type string
MicrophoneLevel: Level calculating by sample calculator.
MicrophoneLevel: minor improvements: removed 'calculateLevel' function