Accounting for case-control imbalance in conditional analysis for gene- or region-based tests

** Note: in v0.36.1, plain text dosage files are no longer allowed as input in step 2 to get rid of the dependence of the boost_iostream library

Bugs fixed: 1. fixed the freq calculation for mean impute for missing genotypes in plinkFile 2. Diagonal elements of GRM are now estimated using markers in plinkFile with MAF >= minMAFforGRM 3. Conditional analysis for gene- or region-based test for binary traits is now accounting for case-control imbalance 4. plain dosage files are no longer supported for step 2 so no external boost_iostream library is needed

** minMAFforGRM is added as a parameter in step 0 and 1, so only markers in the plinkFile with MAF >= minMAFforGRM will be used for GRM ** weights.beta.rare, weights.beta.common, weightMAFcutoff, dosageZerodCutoff, IsOutputPvalueNAinGroupTestforBinary, IsAccountforCasecontrolImbalanceinGroupTest are added as new parameters in step 2