Update changelog
Squashed 'core/' changes from 831eea7..993fcfa

993fcfa Merge tag 'v0.2.0-alpha' into develop
79f002c Merge branch 'release/0.2.0-alpha'
411895a Merge branch 'develop' of github.com:syncany/syncany into develop
5e9312a Merge tag 'v0.2.0-alpha' into develop
19a25af Merge branch 'release/0.2.0-alpha'
0a558be Add release date to changelog
69130d8 Update CHANGELOG.md
3fc105e Allow optional 'File' field to be 'null'
a65eb6e Fix exception in toString method
808045f Merge branch 'release/0.1.12-alpha'
af59537 Merge branch 'release/0.1.11-alpha'
ed18574 Merge branch 'release/0.1.10-alpha'

git-subtree-dir: core
git-subtree-split: 993fcfa980333830943a729c106c80b0f7eb7121
Merge commit 'fef29aef1a0fa39aa0189cd84d943a8799ad8e2c' into develop