When finding an adjacent paragraph, the next_para and prev_para pointers
should be used because they are direct pointers, a constant time
operation.  Instead I found some places in the code that searched through
the general linked list to get to an adjacent paragraph, which is a linear
time operation, depending on the number of rows and runs in between
paragraphs.

The fixme comment is suggesting wrapping a paragraph within a function
that is for moving the selection cursor up or down a line when the up
or down keys are pressed.  The contents fo paragraph aren't being
changed, so there is no need to wrap the paragraph.

More case of searching for the paragraph through the linked list when
is was already previously available.  Since each wrap context is used
for wrapping each paragraph, I decided to add the reference to the
paragarph in the structure.

Rather than get the paragraph from the run, the function allows the
caller to provide the paragraph, since it is already available.  This
reduces unnecessary traversals of lists that take longer as more runs
and rows are in the paragraph.

The ME_RunOfsFromCharOfs function finds the paragraph before finding the
run and offset within the run, so the function may as well be able to
return this paragraph to the caller.  Many callers to the function
instead find the paragraph from the run, which ends up unnecessarily
traversing a linked list of runs within the paragraph.

Whenever ME_InitContext is called, ME_DestroyContext should be used to
clean it up.  This way the context can be extended easily by modifying
those two functions.  Instead, these two places of code just released
the DC, without using ME_DestroyContext, so the created brush for the
margin was not deleted.

These calls to ME_WrapMarkedParagraphs never do anything, and don't make
sense to be called in these places. These places are for ME_MoveCaret,
and ME_ArrowHome, which both don't involve any text being modified, and
all (direct and indirect) calls to these functions are done after the
text has already been wrapped.

The value for nMaxChars can be found easier by using ME_GetTextLength.

msctf: When a Context is created connect to the ITextStoreACP if provided and create and advise our ITextStoreACPSink.