Adding ofx converter, checknum numeric and check balance.

[gpaulissen]

This pull request covers:

• The OFX balance is not reliable if DTEND < DTASOF
• Import of OFX CHECKNUM tag fails for a non-numeric value
• Adding an OFX converter boosts up the usability of beancount importer

[coveralls]

Pull Request Test Coverage Report for Build 123

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-66.8%) to 0.0%

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Totals
Change from base Build 116:	-66.8%
Covered Lines:	0
Relevant Lines:	0

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 169

• 21 of 22 (95.45%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.07%) to 67.115%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
beancount_import/source/venmo_sanitize.py	0	1	0.0%

Totals
Change from base Build 162:	0.07%
Covered Lines:	4562
Relevant Lines:	6590

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 123

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-66.8%) to 0.0%

---

Totals
Change from base Build 116:	-66.8%
Covered Lines:	0
Relevant Lines:	0

---

💛 - Coveralls

[gpaulissen]

Due to ofxstatement 0.6.5 not available on PyPi yesterday, some checks failed. Now ofxstatement 0.6.5 is available on PyPi so it should work.

[gpaulissen]

The checks seem to fail due to beancount-import issues, not due to the latest changes.

[gpaulissen]

After improving the code coverage everything seems right.

[Zburatorul]

@gpaulissen , any interest in getting this over the line?

[Zburatorul]

Looks like you may need to rebase.