Gdbgui

- Add ability to re-map source file paths. Added flags `--remap-sources` and `-m` to replace compile-time source paths to local source paths. i.e. `gdbgui --remap-sources='{"/buildmachine": "/home/chad"}'` (158)
- Add shift keyboard shortcut to go in reverse when using rr (201)
- Pass arbitrary gdb arguments directly to gdb: added `--gdb-args` flag
- Removed `-x` CLI option, which caused major version to change. New way to pass is `gdbgui --gdb-args='-x=FILE'` (205)
- Add "name" to Threads (new gdb 8.1 feature) (P4Cu)
- Fix crash/black screen from "Python Exception <class NameError> name long is not defined" 212
- Fix bug when debugging filenames with spaces (Fix Cannot create breakpoint: -break-insert: Garbage following <location> 211")
- Fix empty frame causes the ui to crash/black screen 216
- Update npm packages; update react to 16.4
- Update prettier rules
- Update tour text + fix typo in tour (nkirkby)

- Add pause button
- Update command line parsing for cmd and --args, change arguments from underscore to hyphen, add option to specify browser (fritzr)
- Add tour
- Run `set breakpoint pending on` on initial connection
- Allow signal to be sent to arbitrary PIDs
- Fix bug when sending signals in Python2
- Move signal component lower in side pane
- Update Rust documentation
- Make requirements.txt point to setup.py's dependencies

- Limit maximum Flask version to prevent `Session expired. Please refresh this webpage.` error
- Rename "premium" to "ad-free"
- Do smarter version checking
- Fix bug when trying to view "about"

- ensure expressions with hex values are parsed and updated appropriately (182)
- improve command line arguments
- use python logging module

- Small bugfix for specific platforms when reading version number

- add option to remove fflush command (179)
- remove react-treebeard and render filesystem w/ new component