test_asm: added test for DCD name+1 (not supported yet)
asm: implemented support for Label.shift field
parser: support label+n syntax
test_asm: fixed test_DCD_name_p_1
added tests/test_mask
mask: fixed bug with masks of >1 part
asm: removed debug print stmt
asm: Label: improved offset() - added checks and support align4
asm: bugfixed previous
asm: LDR Rn,label: use aligned4 offset
Added UXTB Rx,Rx
Added ADD Rx,SP,imm
Added ADR (positive)
Added STR Rn,[SP,imm]
Extended to STR Rn,[SP]
test_asm: typo
fix: replaced DCH with DCW
fixed msgs in LabelError's
asm: fixed ALIGN - now works for 4
asm: workaround for ADR&etc strange error, disabled validation