combine multi-cpp fils into one ;
把多个c/c++文件合成一个;
合成的文件中若有重复的名字则无法获得正确的输出，即使他们不再同一个路径下。
The output is incorrect if some files have the same name, even if they are under different directories.
不允许互相依赖(相互#include)
If existing files #include each other, the program will exit and no output.
首先读入所有要合并的文件，根据他们的#include获得依赖图，根据依赖图确定哪个文件先处理；
处理过程中遇到#include合并的文件的语句，会忽略。
Read all the files which need to be amalgamated.
Get the dependency graph according to #include "" or #include <> sentences.
We can know the handle sequence according to the dependency graph.
If a file #includeother amalgamated files, the #include sentences will be ignored.
创建一个YAML文件{0}指定需要合并的文件和输出文件名。
比如在examples中的example1：当我们在example1文件夹下运行命令python3 amalgamate.py amalgamate.yml所有在include/下的.h文件都会被整合到all.h中，同理all.cpp。
Create a YMAL file {0} which contains the amalgamated files and output files.
For example, the example1 in the folder examples.
When we run the command python3 amalgamate.py amalgamate.yml under the folder example1, all .h files will be amalgamated into all.h.
Similarly to the all.cpp.
python3 amalgamate.py {0}
# examples/example1/amalgamate.yml
all.h:
directory: include/
suffix: ['h']
all.cpp:
directory: src/
suffix: ['cpp']