Add prospector and fix some bugs

[gsnedders]

This is very much for the sake of experimenting with Landscape, to see if it's worthwhile or if it's all just noise.

[landscape-bot]

Repository health increased by 3% when pulling 2a61bb6 on gsnedders:prospector into 52ba64e on html5lib:master.

• 9 new problems were found (including 0 errors and 0 code smells).
• 39 problems were fixed (including 2 errors and 37 code smells).

[landscape-bot]

Repository health increased by 3% when pulling 2a61bb6 on gsnedders:prospector into 43522a2 on html5lib:master.

• 12 new problems were found (including 0 errors and 2 code smells).
• 41 problems were fixed (including 2 errors and 39 code smells).

[landscape-bot]

Repository health increased by 3% when pulling 2a61bb6 on gsnedders:prospector into 43522a2 on html5lib:master.

• 12 new problems were found (including 0 errors and 2 code smells).
• 41 problems were fixed (including 2 errors and 39 code smells).

[hoppipolla-critic-bot]

Critic review: https://critic.hoppipolla.co.uk/r/6054

This is an external review system which you may optionally use for the code review of your pull request.

In order to help critic track your changes, please do not make in-place history rewrites (e.g. via git rebase -i or git commit --amend) when updating this pull request.

[codecov-io]

Current coverage is 89.24%

Merging #218 into master will decrease coverage by 1.06%

@@             master       #218   diff @@
==========================================
  Files            51         50     -1   
  Lines          6809       6735    -74   
  Methods           0          0          
  Messages          0          0          
  Branches       1314       1315     +1   
==========================================
- Hits           6149       6010   -139   
- Misses          497        555    +58   
- Partials        163        170     +7   

Powered by Codecov. Last updated by c8fafd4...3b1f584

[landscape-bot]

Repository health increased by 3% when pulling 95c567a on gsnedders:prospector into 8cb66f2 on html5lib:master.

• 8 new problems were found (including 0 errors and 0 code smells).
• 39 problems were fixed (including 2 errors and 37 code smells).

[landscape-bot]

Repository health increased by 12% when pulling 373fb9c on gsnedders:prospector into c8fafd4 on html5lib:master.

• No new problems were introduced.
• 173 problems were fixed (including 11 errors and 132 code smells).

[landscape-bot]

Repository health increased by 12% when pulling da8f94e on gsnedders:prospector into c8fafd4 on html5lib:master.

• No new problems were introduced.
• 173 problems were fixed (including 11 errors and 132 code smells).

[landscape-bot]

Repository health increased by 12% when pulling db508dc on gsnedders:prospector into c8fafd4 on html5lib:master.

• No new problems were introduced.
• 173 problems were fixed (including 11 errors and 132 code smells).

[landscape-bot]

Repository health increased by 12% when pulling a2b8c11 on gsnedders:prospector into c8fafd4 on html5lib:master.

• No new problems were introduced.
• 173 problems were fixed (including 11 errors and 132 code smells).