set mute button image fixed #59
save voice navigation preference
Merge pull request #63 from mojotech/ce/add_off_state_to_mute-button

CE/add off state to mute button
Translate Split class to Swift.
Remove commented enum
Rename SplitToggle enum
Change stored preference type for splits to a string.
Merge pull request #66 from mojotech/fcanas/swiftening

Translate SplitCalculator and some related classes to Swift
add counter-clockwise routes fixed #65
Merge pull request #67 from mojotech/ce/counter_clockwise_routes

add counter-clockwise routes fixed #65
Slice progress image
Tweak colors and styles on the run view controller
Fix some swift code: remove reference to self, whitespace.
Merge pull request #68 from mojotech/fcanas/appearance

Appearance changes
Make splits table empty cell separator insets zero.
change "end" and "overview" button's font to system-bold & set pace label text color to white50
added constraints to stop overflow of completed distance & set its auto-shrink size fixed #69
Merge pull request #70 from mojotech/ce/dashboard_style

CE/dashboard style
fixed voice nav sound bug fixed #73
Merge pull request #74 from mojotech/ce/fix_nav_voice_bug

fixed voice nav sound bug fixed #73
Eliminate short spurs that can be cleanly removed

Two categories of short spurs, offshoots of straight lines and short
spurs on longer spurs, are now cleanly removed.