Derive Slope Data

- If Alt data present then calculate slope
- Smooth the slope data after calculation
Add Fenix2 to Garmin Devices
Revert "Add Fenix2 to Garmin Devices"

This reverts commit c6112bd13ca4d1d3a407ebe75bc2bff7afd5ca8b.
Add power estimation

Need to be able to add parameters for users to adjust their drag factors
numbers currently work out not too bad for me but needs testing with
more ride files. I have tried it with Mark's Marmotte file and it
doesn't do too bad.

Please feel free to rip it apart and tell me it is wrong - its a good
start hopefully.
Reopen window in maximised state (windows)
Ignore
remove global QApplication *application

.. it is available from the macro qApp anyway.
Revert "Ignore"

This reverts commit 7e3d8dcaaf5cd517f37e4686adfd34c10a74229d.
Change to use Qt saveState & restoreState

Should work on Win, Mac & Linux.
Merge pull request #1002 from jonbev/WindowsWindowState

Reopen window in maximised state (windows)
Wiki - HR-vs-Power

... added HR vs Power chart explanation to Wiki
Merge pull request #1008 from Joern-R/pull2

Wiki - HR-vs-Power
Don't blank CP chart in trends

.. when there is no ride selected / manual entry because
   we plot a date range not a single ride !
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
Add Lactate Threshold section to Science Doc

.. inspired by Prof Seilers layman's document on Lactate Threshold.
   [may still be available here: https://www.dropbox.com/s/vgxjbo32i0o94nt/The%20Lactate%20Threshold_Seiler.pdf]
Avoid saveState() warning on object name

.. by setting it for the unified toolbar on a Mac.
3.1 Release Notes
3.1 FAQ Updates

.. minor changes to reflect how things now work in 3.1
Minor fixup to FAQ