multilevelMatching 1.0.0

Original CRAN release version by Shu Yang (@shuyang1987) and Brian G Barkley (@BarkleyBG).
Added multiMatch() function to carry out all types of matching. This effectively combines multilevelGPSMatch() and multilevelMatchX() into one function. Features include:
- Better output:
  - tidier estimates: see estimateTau()
  - plus more information from under-the-hood: see the impute_mat object for matrix off all imputed potential outcomes.
- Now allows for one-to-many matches for the main matching procedure (and imputing potential outomces). The user may specify M_matches >=1.
- Now allows for one-to-many matches to estimate the variance component. The user may specify J_var_matches >=1.
- Allowed for more user-specified arguments (for fitting PS models) i.e. model_options
Divergence: Using multiMatch() with match_on='existing' does not always return the same results as using multilevelGPSMatch() for matching on the existing (user-specified) generalized propensity scores.
Added S3 methods for print and summary for the multiMatch class
Added S3 methods for print and summary for the multiMatch class
Users can apply the estimateTrtModel() function before using multiMatch() to verify that the model fitted in multiMatch() is the same as the user desires

multilevelMatching 0.1.0

Original package version, released to GitHub by Shu Yang (@shuyang1987). See Release v0.1.0.