Gui fix after merge AUSLAMP-128

[YingzhiGou]

GUI was not functioning correctly due to the changes introduced in merging Geophysics/mtpy and GeoscienceAustralia/mtpy. this pull request intended to bring the GUI back to its working state, and adding new gui test cases for some of the major functionalities.

Description

• GUI design improvements
• bugs in modem.model fixed
• new GUI test cases added
• travis-ci testing environment changes, now dropped tests in Qt4 environment in which the gui may still works but it is no longer supported officially,
• GUI tests have been moved to the last stage of the tests. so it is only run when all mtpy tests are passed
• the pyqt auto install code now install pyqt 5 by default
• GUI now works with the new mtpy imaging package

Motivation and Context

This change is intended to restore the GUI back to working state

How Has This Been Tested?

both new gui tests and existing test cases are passed on windows anaconda environment as well as travis-ci linux environment

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.

[coveralls]

Coverage remained the same at 18.958% when pulling 1af6d706168cf54127fd879f89110be6b15ed660 on gui-fix-after-merge-ALAMP-128 into 390424186c498d4f25e501a5c78b178afd80616a on develop.