Check TIME and time when looking for mixed upper/lower case names in data

[kylebaron]

We'll warn if an incoming data set has both lower- and upper-case versions of some recognized names (like AMT, CMT, etc). TIME / time should also be in that check, but it hasn't been and we just realized it when helping a user in #1098.

We already have the right names to check in this GLOBALS list

> mrgsolve:::GLOBALS[["TRAN_UPPER"]]
[1] "AMT"  "II"   "SS"   "CMT"  "ADDL" "RATE" "EVID" "TIME"
> mrgsolve:::GLOBALS[["TRAN_LOWER"]]
[1] "amt"  "ii"   "ss"   "cmt"  "addl" "rate" "evid" "time"
> mrgsolve:::GLOBALS[["CARRY_TRAN_UC"]]
[1] "AMT"  "CMT"  "EVID" "II"   "ADDL" "RATE" "SS"  
> mrgsolve:::GLOBALS[["CARRY_TRAN_LC"]]
[1] "amt"  "cmt"  "evid" "ii"   "addl" "rate" "ss"