Switch gometalinter to stable

[ValarDragon]

Closes #1338
This switches gometalinter to gometalinter.v2. This also deletes the unused code with go-vendor install, as we can now install things via go get, instead of dep. This also removes the unused make install command in tools.

• Updated all relevant documentation in docs - I don't know of any documentation for what linter we use?
• Updated all code comments where relevant - n/a
• Wrote tests - n/a
• Updated CHANGELOG.md
• Updated Gaia/Examples - n/a
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[ValarDragon]

I believe that test_cover failing unrelated to my code here. I did not change any of the circle CI code for test_cover, or make install in the main Makefile, which is what it calls. I'll make an issue for this.

[codecov]

Codecov Report

Merging #1341 into develop will increase coverage by 1.49%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1341      +/-   ##
===========================================
+ Coverage    64.77%   66.27%   +1.49%     
===========================================
  Files          112       98      -14     
  Lines         6271     5390     -881     
===========================================
- Hits          4062     3572     -490     
+ Misses        1985     1609     -376     
+ Partials       224      209      -15

[cwgoes]

Tested ACK