Added access to array of float data type.

This isn't very elegant. If one subscribes to a 
float array type, for example: 

sim/cockpit2/engine/indicators/engine_speed_rpm

the plugin returns the number of elements in the
array, followed by each of the elements. If a
tolerance is set, it is applied to every element
and if any exceeds tolerance, it'll return that 
element.

I haven't added any code to set values, and will
think some more about perhaps setting up somehow
to collect single values in the arrays.

In the code, values are stored in an array, where
the first element of the array is the number of 
elements that follow. The array is calloc'd but
never freed.
Rename built binary to extplane.xpl automatically, updated documentation. Added Linux binary.
Merge remote-tracking branch 'bobgates/master'
Some minor modifications to Bobgates's float array dataref code.
Finished support for float & int datarefs, some other enhancements.
Support for setting flight loop update interval
disable flushing
Updated binaries dir & README
Moved Qt client code to this project from ExtPlane-Panel.
Minor doc stuff
Work on array datarefs, iirc
Merge branch 'master' of github.com:vranki/ExtPlane

Conflicts:
	client/extplane-client-qt/clientdataref.h
Fixed some array dataref issues
Possible fixes for building on Mac
Merge pull request #1 from vranki/master

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