TwoSampleMR R package

Some optimizations to the code, including:

• Vectorised mr_egger_regression_bootstrap()
• Vectorised weighted_median_bootstrap()
• Deleted duplicated weighted_median() function
• Replace plyr function calls with data.table function calls
  • plyr::rbind.fill(...) to data.table::rbindlist(..., fill = TRUE, use.names = TRUE)
  • plyr::ddply(dat, cols, func) to lapply() over unique combinations + data.table::rbindlist()
  • Added data.table::setDF() calls to convert back to data.frame for compatibility
  • And removed plyr from Imports list
• In flip_alleles() use chartr() instead of 4 gsub() calls
• In random_string() use single call to sample() instead of n calls
• Optimized mr_mode()
• Replaced apply(..., any(is.na())) with complete.case()
• Optimized the mr() function
• Optimized the Optimize get_r_from_lor() function
• Optimized the mr_rucker_bootstrap() and mr_rucker_jackknife_internal() functions
• Replaced sapply() with vapply() in several cases
• Optimized the simple_cap() function
• And a few other minor optimizations