Merge branch 'release/v007' into develop
Add "-O2" compile option
Make inline simple functions of Value class

To achieve this, make tagged pointer constants public.
Generate custom instructions for embed functions
Make Value constructors public
Move map functions inside
Move basic functions from backquote to boot
Change compile order
Simplify Makefile using dependency variable
Generate cxxr functions programatically
Returns end position from `read-from-string`
Ignore result if read-time-eval returns empty
Hide macros only needed at compile time
Fix to work function inlining
Remove unnecessary `do`
Make cxxr functions inline
Simplify `lambda-body-node-get`
Add character type #67
Print character with/without inspection
Convert between fixnum and char