std::tolower is undefined if the argument's value is neither represen…

…table as unsigned char nor equal to EOF (yhirose#761)

Co-authored-by: taoxu <[email protected]>

Fix yhirose#738

Fix problem with invalid range

Fix yhirose#731

Fixed compiler error for old compiler.

Fix yhirose#706

Add `cache_control` parameter to `set_mount_point` (yhirose#688)

* Add `cache_control` parameter to `set_mount_point`

Specifies the Cache-Control header value to return when specified. For example:

```
svr.set_mount_point("/assets", "public/assets", "public, max-age=604800, immutable");
```

* Add default for cache_control

Default to "no-cache", which is implicitly what is happening today.

* Change set_mount_point to accept Headers

* Don't use C++17 destructuring

Fix yhirose#661

Add compression buffer size customization (yhirose#644)

* add compression buffer size customization and small brotli refactor

* allocat brotli buffer once

* add init to brotli decoder buffer

Fix server crash caused due to regex complexity while matching header…

…s. (yhirose#632)

* Fix parsing to parse query string with single space char.

When passed ' ' as a query string, the server crashes cause of illegal memory access done in httplib::detail::split. Have added checks to make sure the split function has a valid string with length > 0.

* Fix parsing to parse query string with single space char.

* Fix server crash caused due to regex complexity while matching headers.

While parsing content-type header in multipart form request the server crashes due to the exhaustion of max iterations performed while matching the input string with content-type regex.
Have removed the regex which might use backtracking while matching and replaced it with manual string processing. Have added tests as well.

* Remove magic number

Co-authored-by: Ivan Fefer <[email protected]>

Co-authored-by: yhirose <[email protected]>
Co-authored-by: Ivan Fefer <[email protected]>