Sort network names case-insensitively

In brief

To match a recent upstream Quassel change, 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