Reduced libload string footprint

[ZERICO2005]

I noticed that rload/ld_relative are only used with a positive offset less than 256, so I was able to save space by storing the offset in 1 byte instead of 3 bytes.

I also changed the following error messages:
ERROR: Missing Library --> ERROR: Library Missing
ERROR: Invalid Library --> ERROR: Library Invalid
This was done so all three error strings start with the same prefix of ERROR: Library .

[runer112]

Could you use the call _ \ .db string, 0 \ _ trick to eliminate rload and ld_relative entirely?

[ZERICO2005]

call needs an absolute address so it won't work in libload

[runer112]

call needs an absolute address so it won't work in libload

Oh, duh.

EDIT: Also it wouldn't even be helpful in this case because you want the string pointer in a register here, not on the stack. Don't know what I was thinking.