c++-mode/cout: improve

Improve this snippet by:

1. Using '\n' instead of "std::endl" to improve the speed of streaming output.
Generally, "std::endl" should be used only when absolutely necessary because
sending "std::endl" flushes the stream which is an expensive operation.

2. Giving user a chance to decide whether to keep the name space prefix
"std::" (type "C-d" to delete the name space prefix).

3. Giving user a chance to decide whether to keep the entire part of " << '\n'".
If kept, she can further decided whether to change the '\n' to something else.
Fix meta.http-equiv

The meta tag in the snippet had the "name" instead of "http-equiv" attribute.
Merge pull request #62 from YorkZ/pull-request

c++-mode/cout: improve
Add cc-mode snippet "forn"

This really is the most frequently used for loop.
Merge pull request #63 from YorkZ/pull-request

Add cc-mode snippet "forn"
Improve cc-mode snippet "if"

* Use a shorter key.
* Give user an opportunity to choose whether to use brace.
Make c++-mode snippet "cout" DWIM

Omit the name space prefix "std::" if the source file already has the statement
"using namespace std;".
Merge pull request #61 from pkkm/patch-1

Fix meta.http-equiv
Merge pull request #64 from YorkZ/pull-request

Improve cc-mode snippet "if"