Small-Plot - wrong Axis Scaling and Labels

... wrong Axis IDs causing the following problems
... X-Axis - not considered time, but high (wrong label/wrong scale)
... Y-Axis - altitude curve not properly scaled
... use similar minimum scale for altitude like AllPlot
... attach Alt-curve first (to be in background)

(used/tested at HrPw window, Split Activity Wizard, Merge Activity
Wizard)
Merge pull request #1010 from Joern-R/pull3

Small-Plot - wrong Axis Scaling and Labels