Tidy duplicate HeartRate related models

HeartRate related models where duplicated on disc but the Model folder
ones weren't included
Missing methods in the IFitbitClient

Some additional methods had been added to FitbitClient but not added to
the IFitbitClient
Merge pull request #34 from WestDiscGolf/SolnTidy

Soln tidy
version update with feature changes

1.1 adds:
* Support for Heartrate
* Blood Pressure
* Better Error messaging with rate limit check
* Bug fixes for time series empty responses
ignore compiled NuGet .nupkg
initial test of a portable/async .csproj
Merge pull request #2 from aarondcoleman/portable-async

Portable async