新增数值计算模块

[zhaoxi-scut]

Pull Request 合并请求准备清单

详情参见此处

• 我同意在 Apache 2 开源许可下为本项目做贡献
• 此 pull request 是在正确的分支上提出的
• 此 pull request 有对应的错误报告或其他待改进的内容
• 我本地的 RMVL 进行了单元测试、性能测试，有对应的测试数据
• 我提交的 feature 有很好的文档记录，并且可以使用 CMake 项目构建示例代码

具体内容

• 添加有关n次多项式、函数插值、函数拟合的内容
• 添加非线性方程求解器
• 添加 Runge-Kutta 方程（组）的内容
• 完善对应文档

单元测试结果

$ bin/rmvl_core_test 
Running main() from /home/zhaoxi/文档/Gtest/googletest-1.14.0/googletest/src/gtest_main.cc
[==========] Running 7 tests from 2 test suites.
[----------] Global test environment set-up.
[----------] 1 test from DataIO
[ RUN      ] DataIO.CornersIO
[       OK ] DataIO.CornersIO (0 ms)
[----------] 1 test from DataIO (0 ms total)

[----------] 6 tests from NumberCalculation
[ RUN      ] NumberCalculation.polynomial
[       OK ] NumberCalculation.polynomial (0 ms)
[ RUN      ] NumberCalculation.function_interpolator
[       OK ] NumberCalculation.function_interpolator (0 ms)
[ RUN      ] NumberCalculation.curve_fitter
[       OK ] NumberCalculation.curve_fitter (0 ms)
[ RUN      ] NumberCalculation.nonlinear_solver
[       OK ] NumberCalculation.nonlinear_solver (0 ms)
[ RUN      ] NumberCalculation.runge_kutta_ode
[       OK ] NumberCalculation.runge_kutta_ode (0 ms)
[ RUN      ] NumberCalculation.runge_kutta_odes
[       OK ] NumberCalculation.runge_kutta_odes (0 ms)
[----------] 6 tests from NumberCalculation (0 ms total)

[----------] Global test environment tear-down
[==========] 7 tests from 2 test suites ran. (1 ms total)
[  PASSED  ] 7 tests.