Bump minimal Go version

Author: longsleep

configure.ac

@@ -33,7 +33,7 @@ AC_SUBST(I18N_COPYRIGHT)
 AC_SUBST(I18N_BUG_ADDRESS)
 
 # minimum required versions
-GO_VERSION_MIN=1.3
+GO_VERSION_MIN=1.4
 NODEJS_VERSION_MIN=0.6.0
 NODEJS_VERSION_STYLES_MIN=0.10.0
 SASS_VERSION_MIN=3.3.0