[#222] Re-export missing files

* Check exported files are found
* Recreate any missing survey zip file
[#223] Check connection status

* Minor code formatting
Merge pull request #224 from akvo/issue/223-network-check

code checked
Merge pull request #225 from akvo/issue/222-reexport-files

code checked
[#226] Bump version number
Merge branch 'develop'
[#226] Update release notes
Merge branch 'develop'