* Make DataStreams bi-directional
* Change send buffer sockopt to Linux minimum
* Fix crash in creating datastreams from badly formatted params
* Fix crash when commiting datastreams with unvalidated options
* Make Input checkbox visible for serial connections
Show greyed out input checkbox for serial data connections
Merge pull request #125 from seandepagnier/optimum-merging

Optimum merging
Merge pull request #124 from stripydog/master

* Make TCP DataStreams bi-directional
Improve "Responsive" GUI interface
Correct to allow current arrow (value) font selection.
Correct OpenGL Track rendering logic
Correct font size calculation method for Mac.
Merge pull request #126 from stripydog/master

Tidy up "Receive" checkbox for non-TCP connections
Correct skewed/rotated DC mode chart render logic.
Improve touch screen dynamics
Further improve touch GUI dynamics
Improve mouse wheel responsiveness for normal (not smooth) zoom ops.
Improve generation of WPTs and RTEPTs for Garmin GPS units by setting the altitude to unknown/zero instead of the MAX_INT default.
Correct for Skewed Transverse Mercator Raster charts (FS#1391)
use chart specific projection for world background chart, and simplify logic
Correct ownship GPS offset rendering logic
Updated UDP datastreams to be input, output or in/out similar to TCP
Correct S57 sector light rendering logic on OpenGL.