Add UTF16 support to PB strings

Provides

fullcase folding string compares

uppercase lower case and titlecase

Declare.s StrChr(v.i) Declare.s StrRight(string$,len)

Prototype StrAsc(str.p-unicode) Prototype StrLen(str.p-unicode) Prototype.s StrMid(str.p-unicode,Position,Length) Prototype.s StrLeft(str.p-unicode,len) Prototype StrCmp(str.p-unicode,b.p-unicode,mode=#CASEFULL) Prototype StrCmpTK(str.p-unicode,b.p-unicode,mode=#CASEFULL) Prototype StrIsUTF16(str.p-unicode) Prototype StrUCase(str.p-unicode)
Prototype StrLCase(str.p-unicode) Prototype StrTCase(str.p-unicode,sep=' ')