Remove AM/PM from time formatting (to be Locale neutral)

... sync all format strings for time input/output to 'hh:mm:ss'
... remove any 'AM/PM' time formats
... remove tr() commands from time formats (since 'hh:mm:ss' is
reasonable around the globe)

... main reason: QT5 does not follow the pure formatting rules any more
(like QT4), but considers the system.locale in formatting as well (so
for system which have no AM/PM, even if the format string is set, the QT
routines ignore that - having some side effect on GC)
Consistent handling of "seconds" and tr('seconds')

... check both for original text and translation when settings precision
for plot
... consistent handling of 'seconds' in GC
Details - Metrics Tab (UI Nit)

... for metrics / time fields ("seconds") don't show units, since the
field is QTimeEdit (in hours)
Merge pull request #949 from Joern-R/pull3

Remove AM/PM from time formatting (to be Locale neutral)
Merge pull request #950 from Joern-R/pull4

Consistent handling of "seconds" and tr('seconds')
Merge pull request #951 from Joern-R/pull5

Details - Metrics Tab (UI Nit)
Compare Pane - sorting improvements

... when sorting first and adding new items, table data is partly empty
and when you next click on item GC dumps (fixed by de-activating the
sorting while refreshing the QTableWidget)
... date fields did not sort due to different formats strings used in
"toString" and "fromString" conversion / added info to translators
... duration and time fields did sometimes not sort (dependent on
time/duration having hours or not)
Merge pull request #952 from Joern-R/pull6

Compare Pane - sorting improvements / fix SEGV
Compare Pane - treatment of duration & problem when adding new metrics

... treat both Time & Duration equally (don't use QTime->toString), but
convert into seconds (since duration can be above 23:59:59 - especially
in Trends view
... table widget looses columns when dynamically adding columns in
Options->Metrics (fixed by setting columnCount to (0) first before
defining the new number of columns)
Merge pull request #953 from Joern-R/pull1

Compare Pane - treatment of duration & problem when adding new metrics
Some more AM/APs

... some more AP/AM changes (hopefulyl the last ones)
... Setttings.h - the GC_DATETIMEFORMAT constant is not used anywhere
(old usages are de-activated)
Merge pull request #954 from Joern-R/pull2

Some more AM/PM adjustments
Translation DE - Update

... translation updates to latest Commit Level
Merge pull request #955 from Joern-R/pull3

Translation DE - Update
Merge remote-tracking branch 'upstream/master'