Update the build image in README.md
Update .travis.yml to extend build matrix with/without tcmalloc
Add pretty-print: format.cpp, format.h
Restructure format, add group and flatten
Add test cases for format
Add color code in format.cpp to test how it looks on terminal
Add Doxyfile (configuration file for Doxygen)
Update .travis.yml to generate doxygen
Add update_doxygen.sh script and use it in .travis.yml
Add some overloads

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Rename/Reorg some kernel files

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add expression offset pair

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add has_free_vars/closed function

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Simplify expr accessor names

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Use operator() for creating applications

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add small demo

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Rename abst_expr -> abst_body

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add abstract/instantiate for kernel expressions

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Refactor instantiate/abstract code

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Remove dead code

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>