Added missing library functions (#51)

Author: BenjiBaruch

_pages/library.md

@@ -257,6 +257,12 @@ function math.lerp(a: number, b: number, t: number): number
 Linearly interpolated between number value `a` and `b` using factor `t`, generally returning the result of `a + (b - a) * t`.
 When `t` is exactly `1`, the value of `b` will be returned instead to ensure that when `t` is on the interval `[0, 1]`, the result of `lerp` will be on the interval `[a, b]`.
 
+```
+math.map(x: number, inmin: number, inmax: number, outmin: number, outmax: number): number
+```
+
+Returns a value that represents `x` mapped linearly from the input range (`inmin` to `inmax`) to the output range (`outmin` to `outmax`).
+
 ```
 function math.log10(n: number): number
 ```
@@ -951,6 +957,22 @@ If an optional 'count' is specified, only 'count' bytes are taken from the strin
 
 Count cannot be larger than the string length.
 
+```
+buffer.readbits(b: buffer, bitOffset: number, bitCount: number): number
+```
+
+Used to read a range of `bitCount` bits from the buffer, at specified offset `bitOffset`, into an unsigned integer.
+
+`bitCount` must be in `[0, 32]` range.
+
+```
+buffer.writebits(b: buffer, bitOffset: number, bitCount: number, value: number): ()
+```
+
+Used to write `bitCount` bits from `value` into the buffer at specified offset `bitOffset`.
+
+`bitCount` must be in `[0, 32]` range.
+
 ```
 function buffer.copy(target: buffer, targetOffset: number, source: buffer, sourceOffset: number?, count: number?): ()
 ```