* move nStart closer to used and initialize it
* Quells warning displayed with `-Wmaybe-uninitialized` flag
* remove unused mnEntries vectors
* add devnet magic bytes to mininode.py
* remove unused governance-misc.h file
* remove old TODO comments
* replace map count/insert w/emplace in instantx.cpp
This feels like an optimization, something about:
```
if map.count(key)
return false
else
insert(pair)
return true
```
... just feels icky. Plus, `vote.GetMasternodeOutpoint()` is only called
once. The previous version might be slightly more readable, however.
* Revert "replace map count/insert w/emplace in instantx.cpp"
This reverts commit d7f876e86336170f2d6d3f20b6af26bcd0dc2b18.
41680f4d94