* perf: break early after parsing required meminfo
Also a match statement for compiler magic.
* perf: pre-allocate strings when reading files
* refactor: remove duplicate .to_string()
* perf: try to print everything in one syscall
println! sends a syscall for each line.
* perf: get rid of duplicate uname syscall
* perf: simplify first letter capitalization
* refactor: directly use key in match statement
Instead of reading multiple files to get the `sysname`, `release`, and
`machine` name, use the `nix::sys::utsname::uname` function which sends a
single uname syscall instead. This increases performance and portability.
From my observations, there are ~10 less syscalls.