Sort network names case-insensitively
## In brief
To match [a recent upstream Quassel change](https://github.com/quassel/quassel/pull/437 ), Quasseldroid should sort networks case-insensitively.
Quassel sorts most things alphabetically in a case-insensitive manner, including the nickname list. The network name list should also be sorted case-insensitively to match.
## Test case
### Setup
Add three networks, `Alpha`, `beta`, and `Freenode`.
### Before
* Alpha
* Freenode
* beta
### After
* Alpha
* beta
* Freenode
issue