Support parsing quirky Chase QFX headers

[fyhuang]

Fix parsing for QFX files exported from the Chase website which seem to have some quirks around the header format. Specifically, the headers begin with an empty line and there is no empty line separating the headers from the rest of the file. An example header:

OFXHEADER:100
DATA:OFXSGML
VERSION:102
SECURITY:NONE
ENCODING:USASCII
CHARSET:1252
COMPRESSION:NONE
OLDFILEUID:NONE
NEWFILEUID:NONE
<OFX>

A sample file chase_cc.qfx is included, with an non-ASCII transaction, to ensure that the headers are parsed correctly (including the encoding/charset).