Bug#814862: fix for qt4 Conflicts

[Ian Haywood]

Ok, I have patched the detection routine in Gambas so if both Qt4 and 
Qt5 are present then Qt5 is loaded.
This means the IDE will actually work (given qt4-webkit is gone, and the 
IDE needs webkit to display the online documentation), but the Conflicts 
isn't required anymore,

I have tested the build and checked the IDE runs.
Gianfranco, can you take a look at this in alioth git and upload the 
package if you are happy?

Thanks

Ian Haywood