New methods for extracting data from a xml

• extract_youngest_year_decimal
• extract_rate_change_reverse_times

Method for fixing values in dimension to 0.

add_rate_change_dates has an offset_earliest option to account for #21.

Method for fixing values in dimension.

Method beast2xml.fix_first_few_dimension_values fixes the first few dimension values for a parameter. This is a great way to fix the sampling proportion to 0 for the period before the first sample.

1.3.9

Fixing bug in adding change dates.

Fixing bug in adding change dates.

1.3.8

Fixing bug in adding change dates.

Options for handling date inputs.

Merge pull request #18 from m-d-grunnill/dates

Added options for handling dates.

Debugged previous ages in xml not deleting.

Debugged previous ages in xml not deleting.

Times in add_rate_change_times are now sorted (descending).

times = sorted(times, reverse=True) in add_rate_change_times.

Times in add_rate_change_times are now sorted (ascending).

Merge pull request #15 from m-d-grunnill/master

times = sorted(times) in add_rate_change_times.

Fixed bugs in adding an initial tree method.

Merge pull request #13 from m-d-grunnill/master

Updated version num & fixed silly bugs in adding an initial tree method.