Added NASM linter

Added NASM linter (for nasm filetype).

test/command_callback/test_nasm_nasm_command_callbacks.vader

@@ -0,0 +1,52 @@
+Before:
+  Save g:ale_nasm_nasm_executable
+  Save g:ale_nasm_nasm_options
+
+  unlet! g:ale_nasm_nasm_executable
+  unlet! b:ale_nasm_nasm_executable
+  unlet! g:ale_nasm_nasm_options
+  unlet! b:ale_nasm_nasm_options
+
+  runtime ale_linters/nasm/nasm.vim
+
+  let b:command_tail =
+  \ ' -X gnu -I ' . ale#Escape(getcwd() . '/') . '  %s'
+  let b:command_tail_opt =
+  \ ' -X gnu -I ' . ale#Escape(getcwd() . '/') . ' -w+orphan-labels %s'
+
+After:
+  Restore
+  unlet! b:command_tail
+  unlet! b:command_tail_opt
+  unlet! b:ale_nasm_nasm_executable
+  unlet! b:ale_nasm_nasm_options
+  call ale#linter#Reset()
+
+Execute(The executable should be configurable):
+  AssertEqual 'nasm', ale_linters#nasm#nasm#GetExecutable(bufnr(''))
+
+  let b:ale_nasm_nasm_executable = '/opt/nasm/nasm'
+
+  AssertEqual '/opt/nasm/nasm', ale_linters#nasm#nasm#GetExecutable(bufnr(''))
+
+Execute(The executable should be used in the command):
+  AssertEqual
+  \ ale#Escape('nasm') . b:command_tail,
+  \ ale_linters#nasm#nasm#GetCommand(bufnr(''))
+
+  let b:ale_nasm_nasm_executable = '~/nasm'
+
+  AssertEqual
+  \ ale#Escape('~/nasm') . b:command_tail,
+  \ ale_linters#nasm#nasm#GetCommand(bufnr(''))
+
+Execute(The options should be configurable):
+  AssertEqual '', ale_linters#nasm#nasm#GetOptions(bufnr(''))
+  let b:ale_nasm_nasm_options = '-w-macro-params'
+  AssertEqual '-w-macro-params', ale_linters#nasm#nasm#GetOptions(bufnr(''))
+
+Execute(The options should be used in command):
+    let b:ale_nasm_nasm_options = '-w+orphan-labels'
+    AssertEqual
+    \ ale#Escape('nasm') . b:command_tail_opt,
+    \ ale_linters#nasm#nasm#GetCommand(bufnr(''))

test/handler/test_nasm_handler.vader

@@ -0,0 +1,30 @@
+Before:
+  runtime ale_linters/nasm/nasm.vim
+
+After:
+  call ale#linter#Reset()
+
+Execute(The nasm handler should parse GCC style output from nasm correctly):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 2,
+  \     'text': "label alone on a line without a colon might be in error",
+  \     'type': 'W',
+  \   },
+  \   {
+  \     'lnum': 4,
+  \     'text': "invalid combination of opcode and operands",
+  \     'type': 'E',
+  \   },
+  \   {
+  \     'lnum': 7,
+  \     'text': "unable to open include file `bar.asm'",
+  \     'type': 'E',
+  \   },
+  \ ],
+  \ ale_linters#nasm#nasm#Handle(357, [
+  \   "tmp.asm:2: warning: label alone on a line without a colon might be in error",
+  \   "tmp.asm:4: error: invalid combination of opcode and operands",
+  \   "tmp.asm:7: fatal: unable to open include file `bar.asm'"
+  \ ])