add windows version merge_pip.exe v1.0.0

+读入两个录像文件，合成画中画视频。合成的流程：
+1. 读入recordfile1.txt，合成为音视频对齐的ts，生成record1_out.txt
+2. 读入recordfile2.txt，合成为音视频对齐的ts，生成record2_out.txt
+3. 读入record1_out.txt和record2_out.txt，生成 record1_record2.txt
+例如：
+命令：merge_pip uid_4165000_20180203013327202.txt uid_811375464_20180203013322272.txt
+
+其中，uid_4165000_20180203013327202.txt 内容如下：
+0.000 4165000_20180203013327202.aac create 
+0.410 4165000_20180203013327612.webm create 
+0.411 4165000_20180203013327612.webm info width=320 height=240 rotation=0
+1418.961 4165000_20180203013327612.webm close 
+1433.849 4165000_20180203013327202.aac close 
+
+
+其中，uid_811375464_20180203013322272.txt 内容如下：
+0.000 811375464_20180203013322272.aac create 
+1.154 811375464_20180203013323424.webm create 
+1.155 811375464_20180203013323424.webm info width=320 height=240 rotation=0
+1520.126 811375464_20180203013323424.webm close 
+1535.109 811375464_20180203013322272.aac close
+
+
+生成 uid_811375464_20180203013322272__uid_4165000_20180203013327202.txt，
+uid_811375464_20180203013322272__uid_4165000_20180203013327202.txt内容如下：
+0.000     1535.290    pip_811375464_20180203013322272.ts
+
+配置文件，merge_pip.cfg：
+如果要修改，windows下在merge_pip.exe同目录下新建merge_pip.cfg文本文件，第一行保存视频编码，第二行保存音频编码;linux 下，merge_pip.cfg保存在HOME目录下的merge_av目录。
+
+第一行，音视频合并时缺省视频编码参数，缺省值为：-vcodec libx264 -level 3.1 -preset veryfast -g 100 -r 20 -bf 0 -vsync cfr
+第一行，音视频合并时缺省音频编码参数，缺省值为：-acodec copy
+第三行，合并画中画时的音视频编码参数，缺省值为：-acodec aac -vcodec libx264 -level 3.1 -preset veryfast -g 100 -r 20 -bf 0 -vsync cfr
+第四行，合并画中画时音视频合并filter参数，缺省值为：-filter_complex "[1:v]scale=w=96:h=72:force_original_aspect_ratio=decrease[b];[0:v][b]overlay=x=0:y=0" -filter_complex amix=inputs=2:duration=first:dropout_transition=2,volume=1
+
+
+