Changed FlatSpark property to maintain proportions' name to 'fixedAspectRatio'
Add link to wiki page with info on Promises
FLEX-34564 Minor changes to spelling, punctuation, grammar and logic.
minor changes/clarifications

Conflicts:
	README
Now, if any ancestor chain of BusyIndicator becomes visible, it will start spinning.
Fixes bug https://issues.apache.org/jira/browse/FLEX-34701
Add latest bug fix
Added some bits about the various ways to get the source code for the SDK

Signed-off-by: Erik de Bruin <erik@ixsoftware.nl>
FlatSpark - Changed property name to 'fixedFontSize' to better describe its meaning