Improvements for testing with external data.

- flexible AddTest() parameter parsing
- added parameter for
  - executable arguments
  - referenced external data files
  - diff data files
- gives fatal errors when a requirement for a specific wrapper or tester is not met

see Applications/CLI/Tests.cmake b/Applications/CLI/Tests.cmake
Fix travis build temporarily, tester test depends on wrapper test.
Allow for test executable which are not targets of ogs, e.g. mpirun.
Added target sync-data on envinf1 only.

This copies all file from ${CMAKE_SOURCE_DIR}/../ogs6-data to
/data/ogs/ogs6-data and then triggers a build on Jenkins which
syncs /data/ogs6-data to opengeosys.org
Added mpirun-wrapper.
added threshold edits in dialogue and removed typo
changed searchByContent() signature
checking threshold values from dialogue and evaluating accordingly
added output of collapsible node ids
added validators and tooltips for input params
added eps value to thresholds to avoid tests for 0.0
added missing include
adjusted comment wording
Make AddTest::PATH relative.

The new AddTest_SOURCE_PATH includes the
ExternalData_SOURCE_ROOT in AddTest.cmake.
Use AddTest_BINARY_PATH for simulation result file.

Used in the diff tester.
fixed typo
Remove debug message.
Merge pull request #7 from endJunction/test-improvements

Corrections for file paths in diff tester.
Merge pull request #530 from rinkk/MeshValidationMargins

Mesh Validation Margins
fixed unconnected signal/slot issue for raster mesh conversion