Release note of hn2016_falwa v0.1.7

This version 0.1.7 has some major updates in function names and library structure.

Major updates:

• Name of functions are all now in small letters.
• The radius of planet (planet_radius) is now an optional input for the functions (default value: Earth's radius).
• The function static_stability can now take in 2D (i.e. zonal mean) or 3D field of potential temperature.
• The syntax in the sample IPython notebooks are updated. (see example/)
• Unittest directory has been set up (tests/) and will be constantly updated.
• A new function theta_lwa has been added to compute surface wave activity (See Huang and Nakamura (2016). It is the longitudinally local version of B^* in Nakamura and Solomon (2010) / Wang and Nakamura (2015)).

Note for existing users

• Please change all characters in the names of functions into small letters.
• The directory of functions can be access via hn2016_falwa.api instead of directly from hn2016_falwa.
• The old function Solve_Uref_noslip has been renamed solve_uref_both_bc. The input fields are the same. The dimension-dependent parameters are functions of input instead of hard-coded in the previous version. Thanks @slubis for reminding.