Added reghdfe as dependency

Author: mcaceresb

build/gtools_tests.do

@@ -101,6 +101,7 @@ program main
  cap ssc install egenmisc, replace
  cap ssc install egenmore, replace
  cap ssc install rangestat, replace
+ cap ssc install reghdfe, replace
  * ftools, compile
  * reghdfe, compile
  }

src/test/gtools_tests.do

@@ -101,6 +101,7 @@ program main
  cap ssc install egenmisc, replace
  cap ssc install egenmore, replace
  cap ssc install rangestat, replace
+ cap ssc install reghdfe, replace
  * ftools, compile
  * reghdfe, compile
  }