Support of multi byte characters in body

See https://github.com/connamara/quickfixn/issues/96
Revert "Support of multi byte characters in body"

This reverts commit 2815c41e98910d6f4b967c0c78d82488a8ea381e.
Fixed previous commit of FieldBase.cs
Workaround to allow SequenceReset messages to omit tag 122 (OrigSendingTime) even when tag 43 (PossDupFlag) = Y. This goes against the FIX specification, but it is common for exchanges etc to omit this field.

Utilised by adding the following line to the settings config file:

RequiresOrigSendingTime=Y

Default behaviour is to require the field, as per the FIX specification.
Bug fix
bug fix
documentation and comments for DoPossDup()
Improve code readability
Chunked resends are now sent "on-demand" instead of all-at-once

When MaxMessagesInResendRequest is set, QuickFIX generates multiple
"chunked" resends - and all of them at once. The CME rejects the second
resend complaining that a resend is already in progress (the first).

Modified the resend logic to send the next chunk only when the first one
is complete (i.e. when the last seqnum of the first has been received).
Fixed field namespace bug
Corrected acceptance test for MaxMessagesInResend for delayed chunking
Merge branch 'master' of github.com:andbjorn/quickfixn into 97

Conflicts:
	QuickFIXn/Parser.cs
unit test for non-ascii in a stringfield
parser unit test
correct fixtest to be able to send utf-8; add a utf-8 test
changelog and credit
add session creation file to file store (#139)
some SessionSchedule refactoring, plus new tests and function stubs (#139/#144/#151)
corrections to testAdjustDateTime
implemented SessionSchedule.GetSessionRange for daily sessions