Add test cases for the proxy, and do some tiny fixes.

the fixes are:
1. add "content-type" in headers for when dealing with localresponse
2. make a more accurate tip for throttle rate when lower than 1
3. make the crtMgr funcionality a more independent one
4. uppercase the request header before sending it out

update the tip

test/data/headers.js

@@ -0,0 +1,28 @@
+/*
+* 用于放置所有header信息的测试数据
+*
+*/
+
+// Get 和 Post共有的header信息
+/*eslint max-len: ["off"]*/
+const CommonRequestHeader = {
+    Accept: 'application/json;charset=utf-8,text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
+    'Accept-Charset': 'utf-8',
+    'Accept-Encoding': 'gzip, deflate',
+    'Accept-Language': 'zh-CN',
+    'Accept-Datetime': 'Thu, 31 May 2007 20:35:00 GMT',
+    'Authorization': 'Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==',
+    'Cache-Control': 'no-cache',
+    'Connection': 'keep-alive',
+    'Cookie': 'testCookie1=cookie1; testCookie2=cookie2',
+    'Content-Type': 'application/x-www-form-urlencoded',
+    'Date': 'Tue, 15 Nov 1994 08:12:31 GMT',
+    'Origin': 'http://localhost',
+    'Pragma': 'no-cache',
+    'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36'
+};
+
+module.exports = {
+    CommonRequestHeader
+};
+

test/data/test.css

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+.test {
+    display: block;
+}

test/data/test.js

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+function test () {
+    console.info('This is nothing but a js file, to test the js download');
+}

test/data/test.json

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+{
+  'testkey': 'this is just a normal json file'
+}

test/data/test.svg

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+<?xml version="1.0" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg xmlns="http://www.w3.org/2000/svg">
+<metadata>Copyright (C) 2016 by original authors @ fontello.com</metadata>
+<defs>
+<font id="fontello" horiz-adv-x="1000" >
+<font-face font-family="fontello" font-weight="400" font-stretch="normal" units-per-em="1000" ascent="850" descent="-150" />
+<missing-glyph horiz-adv-x="1000" />
+<glyph glyph-name="glass" unicode="&#xe800;" d="M948 746q0-19-24-43l-353-353v-429h179q15 0 25-10t11-25-11-25-25-11h-500q-14 0-25 11t-11 25 11 25 25 10h179v429l-353 353q-24 24-24 43 0 13 10 21t21 9 24 3h786q13 0 24-3t21-9 10-21z" horiz-adv-x="1000" />
+
+<glyph glyph-name="music" unicode="&#xe801;" d="M857 725v-625q0-28-19-50t-48-33-58-18-53-6-54 6-58 18-48 33-19 50 19 50 48 33 58 18 54 6q58 0 107-22v300l-429-132v-396q0-28-19-50t-48-33-58-18-53-6-54 6-58 18-48 33-19 50 19 50 48 34 58 17 54 6q58 0 107-21v539q0 17 10 32t28 20l464 142q7 3 16 3 22 0 38-16t15-38z" horiz-adv-x="857.1" />
+</font>
+</defs>
+</svg>