bump version in files

Release version 1.3.1

Beta version 1.3.0

apply llvm-header-guard, llvm-namespaces (#218)

run clang-tidy checks llvm-header-guard, llvm-namespaces to update code style

make jinja2cpp conan-friendly again (#217)

* make jinja2cpp conan-friendly again
* fix c++20 build mode

Manage global options with 'add_compile_options' instead of direct ma…

…nipulation

[skip ci] Update readme

Fix ref to value-ptr-lite

[skip ci] Update readme

Add space trimming control and global environment settings

* Add space trimming control and global environment settings

*  [skip ci] Update ReadMe.md

* [skip ci] Update CMakeLists.txt install script