PWX support make/model for TP.com upload

.. on request from TrainingPeaks we now add the make and model
   elements to a PWX file.

Fixes #593
Add Fatigue Profiling Peak Power Durations

.. added for 2,3,8 and 90m peak power

.. user defined intervals for peak power/vam/np et al
   are still planned for v3.1

Fixes #595
LTM Show top 1 not 5 by default

.. Top 5 is a bit much, in reality defaulting to highlight
   just the top value is more useful and shouldn't lead to
   an ugly chart.
Merge branch 'master' of github.com:GoldenCheetah/GoldenCheetah