Add initial wizard UI (#6)
Add some initial elements to the outputs page
Add some basic InputsPage widgets
Implement the input path(s) loading and browsing
Implement the folders add/remove buttons

This also includes a small number of icons from the open source
Oxygen Icons set (from KDE). These have been included verbatim.

http://download.kde.org/stable/4.13.3/src/oxygen-icons-4.13.3.tar.xz
Use the Oxygen theme anytime there's no default
Tweak the inputs page slightly
Define sorting and default selections
Rename the hookInputFolder function to defaultInputFolder
Build the GUI app in Travis CI

This doesn't run any additional tests or anything, just exercises the
build process, which will help to catch things like missing resources.
Implement InputsPage::isComplete
Use a combobox for the output folder
Implement output field loading / saving
Use the virtual QWizardPage::initializePage method
Load the previous output path from settings
Add initial output filename format information
Implement loading/saving filename format
Require at least one output format.
Add a conversion-results wizard page
Size the progress bar appropriately