[transport] Divide transport into appropriate files

Put functions of the initial transport files to the appropriate places in
wien2k_converter and sumk_dft_tools
[transport] Case Sigma=0 included (LDA_only)

Some other minor corrections.
[transport] Change names, correct some issues in merge

Simplify writing/reading from h5
[transport] API changes
[transport] Added new test case for transport code, some other minor changes
[transport] Add transport test to CMakeLists.txt
[transport] Delete obsolete SumK_Transport files
[transport] Minor fixes, all tests now pass
[transport] Minor changes lost in rebase
[transport] Preliminary tidiying up of transport converter