fix(annotations) isReference now correctly triggers a save when it is modified

The $intermediateEvent flag was never lowered meaning changes from the single edit view that did not trigger drawabox rendering never got saved.
The flag is reset on each modelUpdated function call now.
Merge pull request #127 from QutBioacoustics/reference-annotation-binding

fix(annotations) isReference correctly triggers a save when it is modified
Work on correct grid-labels

GridLabels require absolute start date of recording - added it into unit converter.

Added tests to the unit converter and updated all usages of it.

Also refactored Media creation in listen so that it properly transforms its value.
Then fixed associated bugs with Media model (sample rate was set on the resource not on this)
	and added appropriate unit tests.
Grid line labels corrected for Annotation Library
Attempt to support code coverage
Attempt 2 to support code coverage
Debugging code coverage
More debugging the code coverage
More debugging code coverage
More debugging code coverage
More debugging code coverage
Added coverage badge
Updated karma-coverage
Merge pull request #131 from QutBioacoustics/grid-labels

fix(gridLines) Fix grid labels, Fixes #121
updated dependendcies
modified karma so line cov does not run while editing the site interactively
Added unit converter tests and extra checks for malformed input data
fixed phantom coverage reports
chore(release): v0.0.18
Fixed lcov preprocessor being included in dev build