Improve support for installing with cget (pantor#88)

* Improve support for installing with cget

* add specific version, clean cmake

* fix version to "v2.1.0"

Change std::stringstream& to std::ostream& in render_to() (pantor#76)

* Change std::stringstream& to std::ostream& in render_to()

Fixes pantor#75

* Expose render_to

* Update readme with example of render_to

Inja v2 (pantor#67)

* inja2

* header only

* reduce dependencies

* code cleaning

* c++17

* use stdc++

* code cleaning

* infrastructure

* header only

* add infrastructure

* fix tests

* use minimum clang 6

* code cleaning, polyfill for c++11

* fix some file tests

* fix readme

* update appveyor

* fix polyfill and ci

* fix polyfill

* fix ci?

* test msvc __cplusplus

* add doxygen

* activate all tests

* code cleaning

* add coveralls, set default to dot notation

* add html test

* add doxygen comments

* test single_include file

* change build folder in appveyor

* correct make arguments in appveyor

* fix appveyor arguments

Fixed warning in 64-bit windows build (pantor#24)

* Fixed passing callback arguments as reference

* Another passing as const reference instead of new instance

* Implemented variable number of parameters
-  extended function "function_regex" to pass minimum and maximum parameters. if minimum=maximum, all params are required, if minimum = 0, all params are optional.....
- for single parameter there is different regex (created by the same function_regex function) to allo read sort([1,2,3]) as one parameter
- extended Match to test if group is valid, so only valid params are filled to params vector
- new function arguments_count to test number of arguments passed to callback

* unit tests for updated callbacks with variable number of params

* merge with last version

* Optimized passing arguments as const reference

* Fixed warning on 64-bit windows (conversion from 'size_t' to 'int', possible loss of data)

Fixed warning in 64-bit windows build (pantor#24)

* Fixed passing callback arguments as reference

* Another passing as const reference instead of new instance

* Implemented variable number of parameters
-  extended function "function_regex" to pass minimum and maximum parameters. if minimum=maximum, all params are required, if minimum = 0, all params are optional.....
- for single parameter there is different regex (created by the same function_regex function) to allo read sort([1,2,3]) as one parameter
- extended Match to test if group is valid, so only valid params are filled to params vector
- new function arguments_count to test number of arguments passed to callback

* unit tests for updated callbacks with variable number of params

* merge with last version

* Optimized passing arguments as const reference

* Fixed warning on 64-bit windows (conversion from 'size_t' to 'int', possible loss of data)

Merge pull request pantor#4 from jowr/master

Add inja to hunter package manager