doc development/en: use "Groonga" notation for English
Merge pull request #151 from cosmo0920/use-Groonga-notation-development-en

doc development/en: use "Groonga" notation for English users

Patch by cosmo. Thanks!!!
test: fix wrong location

It is a test for --scorer not --filter.
test command: add --filter returns bool case
Support all int32 castable values as valid filter score value

For example, Groonga uses unnatural score for --filter '"29"' case
without this change because Groonga processes "29" as uint32 value
instead of string value.

Groonga casts --filter-ed result to int32 value before treating it as
score value with this change.
Adjust "||" behavior to ECMAScript

"x || y" returns the first not false value. If x is not false value,
"x || y" returns "x" itself not "true". If x is false value and y is
not false value, "x || y" returns "y" itself not "true".

If both "x" and "y" are false value, "x || y" returns "false". It is
not changed.

Before:

    null || "string value" -> true
    null || null           -> false

After:

    null || "string value" -> "string value" (changed)
    null || null           -> false          (not changed)
test: add more "x || y" cases
test: use more meaningful name
Adjust "&&" behavior to ECMAScript

"x && y" returns false if "x" or "y" is false value, "y" if both "x"
and "y" is not false value.

Before:

    29 && "string value" -> 1
    null && true         -> 0

After:

    29 && "string value" -> 29    (changed)
    null && true         -> false (changed)

The commit message of
c007a6819aa3840054297b061b35066deaf173f1 (supports "x || y") is
wrong. "x || y" returns 1 or 0 not true or false.
snippet_html: returns null when no snippets is found
Treat vector value as score "1"
test: fix test location

It is a test for "score" not "||".
Treat non castable score value like "string value" as score "1"
test: simplify

The important thing in the test is "_score" value.
test: follow "x || y" and "x && y" return object itself change

Float value that is less than 1.0 are all invalid score value because
score is int32 and valid score is greater than or equal to 1.
Add missing endif comment
Update endif comment
Use "!defined(__GNUC__)" instead of "defined(_MSC_VER)"

Because fstat uses the condition.
doc: add description about POST method

Suggested by @Yappo. Thanks!!!
doc: use capitalized "Groonga"