Refactor BSPline and Spiro to remove duplicated functions

2Geom sync - initial commit

cleanup spiro code

clean up spiro code

Update 2Geom to pull in integer rectangle class

update to latest 2geom !

Remove remnants of old node tool

Fix LPEs and break mask transform undo

lpe-spiro: fix problem with rounding and very nearly zero closing line segments

call default setup_nodepath for lpe-spiro, to get correct color of the helperpath

Merging from trunk

make spcurve::first_point and last_point boost::optional

simplify lpe spiro code by using new "is_straight_curve" method

use nodetype helper function to determine nodetype within lpe-spiro

lpe spiro: if path is closed it does not matter to what initial pointtype is initialized.

remove more NR:: from live_effects code

update to 2geom rev. 1507

remove debug messages from last commits

fix lpe-spiro for smooth closing points

2geomify lpeSpiro

noop: be more consistent with function names (get_pathvector => set_pathvector)

LPE Spiro: don't catch all exceptions, only the ContinuityError

catch cases where LPE Spiro generates non-continuous paths

whitespace

Add option to either suppress path flash for items with LPE (e.g., spiro splines use this) or display it permanently while the item is selected.

complete adding const to have only NArtBpath const * get_bpath() const; for accessing the protected member of SPCurve. Nowhere in Inkscape source is the path data changed of SPCurve, except within SPCurve's own methods ! So removed the non-const NArtBpath* get_bpath.

- try to use more forward declarations for less dependencies on display/curve.h - change _bpath to private member of SPCurve, obtain and set with get_bpath and set_bpath. - added const methods, so protect changes to _bpath in SPCurve

make determining smooth nodes more robust

struct SPCurve => class SPCurve change all sp_curve_methods functions to SPCurve::methods.

Warning and whitespace cleanup

suppress helperpath and handles showing for LPESpiro

suppress helperpath display for spiro

Spiro splines LPE using code by Raph Levien