Bug fixes for split transactions

[dospuntos]

• Replace "Split transaction" with "Split"
• Restore orginal category when un-splitting
• Update catkeys
• Don't validate 'Split' category for split transactions
• Remove 'Split' as shortcut when entering new transaction

[dospuntos]

@humdingerb - I added the new translations for "Split"

[dospuntos]

@humdingerb - This should be ready to merge now, if it looks OK with you.

[humdingerb]

Looks good, but there are still a couple of B_TRANSLATE_CONTEXT("Split", "CommonTerms") that should also be converted to a B_TRANSLATE_ALL (I assume all the 'noun' variant).

[dospuntos]

Looks good, but there are still a couple of B_TRANSLATE_CONTEXT("Split", "CommonTerms") that should also be converted to a B_TRANSLATE_ALL (I assume all the 'noun' variant).

Thanks for checking, I've updated them.

[humdingerb]

Thanks!