* Lazy MathData to avoid unneeded interpretation of macro definitions

* Lazy MathData to avoid unneeded interpretation of macro definitions
* DocIterator as MacroPosition
* Iterative search for macro in scope until a visible one is found.
This include the ability to resolve macro inside nested text insets.
* Speed up macro lookups by factor 2: only getMacro(name) call, no
further hasMacro(name) call before
* Both way child/master support
* Correct macro scope for multi-paragraph environments
* Correct macro scope for multi-depth-paragraphs
* Buffer::updateMacros made const
* Update macros when loaded (of master and child)
* Do not remove too many braces when unfolding a macro. This could
lead to a data loss because the relationship between arguments of
macros can be mixed up if nested macros are unfold at once.
* Reduce dependencies to MetricsInfo in MathMacro
* Update macros when needed. Normally it's done just before doing
metrics. But in cases without a brace around some constructs (like
\left(bla\right)) there is some help needed.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@22241 a592a061-630c-0410-9148-cb99ea01b6c8