Implementation of text swing (step1)

added swing tab

swing settings tab in staff text properties

Implemented step 2 of swing implementation using staff texts

Added call for updateSwing in stafftextproperties

Initial page for dialog changed

System flag enabled for swing parameters

saving and loading with text specified swing implemented

removed extra print statement

fixed formatting

Added groupbox to make the default behavior to no change in swing

fixed indentation in stafftextproperties

fixing conflicts in staff.h

Removed writing of setSwing to file

Removed SwingParameter member from staff and fixed layout of swing tab in dialog

fixed the issue with disabled controls

Added tests for staff text implementation of swing playback

cleaned up the code

Swing playback using staff texts implemented, facilitating local control over swing parameters and tests for the same added

Cleaned up code

Cleaned up code further

Swing Playback using staff texts implemented

Cleaned up code further

Cleaning up code further

Using MScore::division in place of 480 as ticks

Modified test files according to new usage of MScore::division

Removed unwanted printf statements

Using strings to write to xml rather than doubles for swingUnit

Replaced 240 and 120 in terms of MScore::division in stafftext:write

Using TDuration to write to xml

Replaced string literals by TDuration for style parameters

Replaced "off" with "" in style.cpp

Set defaults for unit and ratio in constructors

Removed usage of two structs for SwingParameters

Changed order of assignments in setSwingParameters

Swing playback using staff-texts implemented and tests added
Replaced swingUnit by unit and swingRatio by ratio, also made _swing private
Merge pull request #1105 from shredpub/textswing

Swing Playback implementation using staff texts