Merge into master for v2.1.0 release

[jtalier]

This most notably has the updated server present. In addition updates/ fixes for the data view, limits window, and tank system checking. List of changes below:

Server:

• Backend completely re-written for improved readability and better thread support
• Three thread system to allow for graphics updating even when server thread is busy
• Better support for shutting down threads and ensuring operations are thread safe
• Filtering options for viewing packets
• Flash data download progress can be viewed
• New command log window
• Server tracks but does not display update frequency

Data-Viewer:

• Fixed slider behavior so that it doesn't include ranges of data that are no longer stored in the program (defaults to last 15 minutes)

Limits Window:

• Expanded range selection for limits
• Each end of the range can be set to ≤, <, and ∞ (for the upper limit) or -∞ (for the lower limit)
• Setting either end of the range to +/- ∞ is effectively the same as having no bound for that end

Tanks:

• Tanks can now 'Override System Indicator Light' if they are not supposed to have avionics attached to them

Bug Fixes:

• 106

• 116

• 131

• 145

[jtalier]

don't merge this until we update the version number

[juliexwu]

Data-viewer:

• Fixed slider behavior so that it doesn't include ranges of data that are no longer stored in the program (defaults to last 15 minutes)

Limits window:

• Expanded range selection for limits
• Each end of the range can be set to ≤, <, and ∞ (for the upper limit) or -∞ (for the lower limit)
• Setting either end of the range to +/- ∞ is effectively the same as having no bound for that end