Changes to import IFrameDialog correctly from the library

[AJIXuMuK]

Q	A
Bug fix?	[x]
New feature?	[ ]
New sample?	[ ]
Related issues?	mentioned in #52

What's in this Pull Request?

• IFrameDialog export changed from default to general one to be importable from the library in the same way as other controls
• IFrameDialog example is added to the test web part page of the project

[codecov-io]

Codecov Report

Merging #53 into dev will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev      #53   +/-   ##
=======================================
  Coverage   77.91%   77.91%           
=======================================
  Files          10       10           
  Lines         335      335           
  Branches       78       78           
=======================================
  Hits          261      261           
  Misses         55       55           
  Partials       19       19

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[estruyf]

Thanks @AJIXuMuK I merged it and will get added to v1.2.4.

[AJIXuMuK]

Awesome!
Thanks for the quick merge!